The present invention relates to coagulation probes or coagulation forceps for endoscopes, and especially hysteroscopes, having a plastics-coated head or jaws in which is housed an electrical heating element which is connectable to an electrical current supply source. Hereinafter, such a probe or forceps will be referred to as "a surgical instrument of the kind described".
To prevent uncontrollable HF currents from existing when areas of tissue are being coagulated, in human body-cavities, particularly in hysteroscopy, the practice has been adopted in recent times of using coagulation temperatures of approximately 110.degree. to 150.degree.. This was achieved by mounting heating elements in the heads of probes or the jaws of forceps, for the purpose of inactivating thermolabile tissue. In this way the danger of current being transmitted into the tissue, especially in the case of hysteroscopy in the ostia of the fallopian tubes or in gynaecological laparoscopy (e.g. for sterilising or temporarily sterilising women) was removed.
While a coagulation is being performed it has hitherto been necessary for the doctor to switch on the heating current and then switch it off again after the coagulation period, and then observe a cooling-off period for the probe-head or the jaws of the forceps before the probe or forceps can be removed. These operations hamper the activities of the doctor while he is observing the coagulation process.
Therefore, it is an object of the invention to provide a probe or forceps which relieves the doctor of the need to switch off the instrument eventually and of the need to observe waiting times during tissue coagulation, while at the same time keeping the coagulation period and the cooling down period for the probe or forceps under automatic supervision.